A motion transmission system in a bicycle comprises a chain extending between toothed wheels associated with the axle of the pedal cranks and with the hub of the rear wheel. When there is more than one toothed wheel at at least one of the axle of the pedal cranks and the hub of the rear wheel, and the motion transmission system is therefore equipped with a gearshift, a front derailleur and/or a rear derailleur is provided for. In the case of an electronically servo-assisted gearshift, each derailleur comprises a chain guide element, also called cage, which is movable to move the chain among the toothed wheels in order to change the gear ratio and an electromechanical actuator to move the chain guide element. The actuator in turn typically comprises a motor, typically an electric motor, coupled with the chain guide element by means of a linkage such as an articulated parallelogram, a rack system or a worm screw system, as well as a sensor of the position, speed and/or acceleration of the rotor or of any movable part downstream of the rotor, down to the chain guide element itself. It is worthwhile noting that slightly different terminology from that used in this context is also in use.
Control electronics changes the gear ratio automatically, for example based on one or more detected variables, such as the travel speed, the cadence of rotation of the pedal cranks, the torque applied to the pedal cranks, the slope of the travel terrain, the heart rate of the cyclist and similar, and/or, of particular interest for the present invention, the gear ratio is changed based on commands manually input by the cyclist through suitable control members, for example levers and/or buttons.
A control device of the front derailleur and a control device of the rear derailleur—or just one of the two in the case of simpler gearshifts—are mounted so as to be easy for the cyclist to manoeuvre, normally on the handlebars, close to the handgrips thereof where the brake lever is also located for controlling the front and rear wheel brake, respectively. Control devices that allow to drive both a derailleur in the two directions and a brake are commonly called integrated controls.
By convention, the control device of the front derailleur and the brake lever of the front wheel are located close to the left handgrip, and vice-versa the control device of the rear derailleur and the brake lever of the rear wheel are located close to the right handgrip.
It is well known that in bicycles, in particular if intended for racing, there is an ongoing search for solutions to improve performance. In particular, an objective of bicycle designers is to constantly improve the ease of access to the control devices, so that the cyclist is in a position to be able to concentrate on the physical effort without having to worry about actuating the controls. This requirement is clearly more important when the bicycle is intended to be used in high-level cycling races.
For this purpose, it is for example known to equip bicycles with one or more redundant control devices also known as remote or additional control devices.
Such redundant control devices are positioned on the handlebars and/or on the frame in the positions most easily reached according to the particular postures taken up by the cyclist in the different phases of a race.
The most common redundant control devices generally comprise at least one pair of buttons and/or levers projecting from a containment casing, and means for imparting an electrical control signal, typically comprising a pair of switches actuated by the buttons.
In particular, by acting on a first button, in general called UP, the cyclist typically commands upward gearshifting and by acting on a second button, usually known as DOWN, downward gearshifting is typically commanded.
As a function of the upward and downward gearshifting control signals imparted through the switches of the control devices, a respective derailleur associated with the rear wheel and/or with the axle of the pedal cranks is actuated so as to move the chain among the different toothed wheels respectively associated with the rear wheel and/or with the axle of the pedal cranks, so as to carry out gearshifting and establish the gear ratio selected by the cyclist.
The control signals are typically transmitted to the derailleur by means of an intermediate unit. It is also known from U.S. application Ser. No. 14/290,646, which is incorporated herein by reference as if fully set forth and which claims priority to Italian Application No. MI2013A000895, to provide a direct connection between each control device present on the bicycle and the respective derailleurs.
The control device can comprise other switches, including for example a control switch called MODE for selecting an operating mode and/or a control switch called SET for setting the various parameters of the system.
The Applicant has realized that in known bicycle electronic systems, provided with one or more redundant control devices, the electrical connection between the control devices and the rest of the electronic system, in particular the derailleurs, entails a fair number of drawbacks.
The Applicant has found that such a type of connection requires the use of a large amount of conductors arranged at or close to the handlebars, making such an area accessible only with extreme caution not to hit and/or pull the multiple cables.
It is also known to provide a bicycle electronic system in which the main control device is provided with an input connector and with an output connector, thus being able to be interconnected between the intermediate unit and the redundant control device.
The Applicant has however noted that such a solution, while reducing the overall amount of cables that it is necessary to arrange at or near to the handlebars for the connection of the control system, is not very reliable. Indeed, the connection in series between the two control devices brings about that a possible malfunction of the main control device also makes the redundant control device unusable.
The Applicant has also found that such a bicycle electronic system needs a specially designed main control device, which differs from the redundant control device at least in the amount of connectors with which it is provided. Therefore, it is not possible to exploit large-scale effects, at least for the production of the redundant control device, in general used only in bicycles intended for high level races.
Moreover, the control devices of a bicycle electronic system currently used mostly provide for the pair of buttons UP and DOWN to be arranged on a same face of the containment casing of the electronic components of the control device.
The Applicant has noted that, depending on the assembly of the control device on the handlebars or on the bicycle frame, the actuation of buttons arranged on a same face necessarily requires, in a first scenario, the thumb to be continually moved between one button and the other according to the command that is to be imparted, or, in a second scenario, the commands to be imparted through the aid of two of the remaining fingers of one's hand.
The Applicant has found drawbacks associated with both scenarios: in case the actuation takes place by just the thumb, it is necessary to continually reposition the thumb, so that it is able to actuate the correct button each time, in this way introducing delays and imprecisions in actuation; in the scenario in which the actuation takes place through the remaining fingers of one's hand, conversely, there is a loss of the efficiency of actuation known to be associated with the thumb.
Other embodiments of control devices of bicycle electronic systems provide for buttons arranged on opposite faces, therefore able to be actuated using the index finger and the thumb.
However, the buttons of such devices are generally located in a same position in the respective face of the casing, therefore actually arranged in a corresponding position with each other.
The Applicant has noted that the actuation of buttons thus arranged is however not very convenient, in particular due to the substantial difference in length of the fingers used for actuation, which does not make it easy to operate in opposite points corresponding to one another.
Furthermore, in currently used bicycle control devices, the manual actuation axis of the button coincides with the actuation axis of the electronic switch actuated by the button.
The Applicant has found that satisfying this structural requirement brings about particularly strict design restrictions that do not allow optimization of layout, overall requiring greater bulk.
Last but not least, in known control devices of a bicycle electronic system, the buttons are generally constrained to the casing through the use of pins passing through slots, which allow the button to move by rotating by a small amount between its rest position and the switch actuation position.
The Applicant has noted that such a solution of constraint between the buttons and the casing takes long assembly times, lengthening the time needed overall to make and manufacture the control devices.
The problem at the basis of the invention is to avoid the aforementioned drawbacks, in particular providing a control device of a bicycle electronic system that does not require the use of multiple connection cables to be positioned at the handlebars, and at the same time ensures operating reliability.